Centrifugal unloader



July 6, 1926. 1,591,393

R. c; MCALLISTER CENTRIFUKGAL UNLOADER Fi led 0st. 5 1-925 2 Sheets-Shetl INVENTOR gimondamilllis'fin KZJ/Q M d 4 /a A ,ML

' ms ATTORNEY July s, 1926. 1,591,393

R. C. M ALLISTER CENTRIFUGAL UNLOADER' Filed Oct. 5 1925 2 Sheets-Sheet2 INVENTOR @MondaMJZHIidZ'I-p Patented July 6, 1925.

UNITED STATES PATENT OFFICE.

,RAYMOND c. MGALLISTER, or PAINTED Post, NEW Yo mnssIoNoR 'ro INGERSOLL-RAND comrenror JERSEY CITY, NEW JERSEY, A CORPORATION or NEw'JnEs Y.

cENTRIEUoAL UNLOAD R.

Application filed October 3, 1925. Serial No. 60,142. M

P; Pins V extend into the guides T' and are This invention relates toaircompressor unloaders, and more particularly to that type which isadapted to unload'the compressor to enable the driving element to accelerate before loading the compressor.

Electric motors or internal combust on engines, as is well known, havelow startlng torque. In cases in which they are used for driving aircompressors it is desirable that the load be removed in order either topermit the engineto accelerate, in the case of an internal combustionengine, or, in the case of an electric motor, to prevent heavy drafts ofcurrent at starting.

'One object of this invention is to unload the compressor while themotor is accelerating by means which at high speeds of the motordisengage, so that there are no wearing parts engaged whilethecompressor 2 operating at normal speed.

Other objects and advantages of the mvention will be in part obvious andin part pointed out hereinafter.

In the drawin forming part of this specification in whic similarreference characters refer to similar parts, I

Figure l is a longitudinal vertical section through a compressorprovided with an unloader constructed in accordance with the practice ofthe invention,

Figure 2 is a view of the compressor, the unloader being shown insection along the line 22 looking in the direction of the arrows, and

Figure 3 is a cross section of the unloader along the line 3'-3 lookingin the direction of the arrows.

Referring to the drawing, the compressor includes a casing A havingcylinders B 4 formed integrally therewith, and a crank shaft C providedwith main bearings D, and

cranks E for o erating'the pistons F in the cylinders B. X cylinderliead G houses the intake valve assemblies for the cylinders B,

each valve assembly including a valve seat.

H, an inlet valve J and a valve back stop Ksuitably held together by abolt L. The

valve seats H are held in position in apertures O by means of cages Pwhich are screwed into a threaded aperture Q in the head G. Forunloading the compressor the valves J are adapted to be pressed fromtheir seats H by spiders R provided with plungers S arranged to slide inguides '1 mounted in suitable apertures U of the cages adapted to pressagainst theupperfaces of the plungers S to epress thespiders :R forpressing the valves J from their seats: The interior of the cages P isadapted to com municate with the inlet manifold through a plurality ofapertures'X in the WHlHSEOf the cage P. i as] In accordance with thepracticeof'j'this invention the unloading mechanism. is' operatedthrough a medium. of a shaft Y driven by the compressor through a gear Zmounted at the end of. the crankshaft C and 'a pinion b keyed to theshaft Y. The shaft-Y is journalled in a boss (1 preferably formedintegrally with a cover e attached in any suitable manner to the'endf ofthe crank case A. A disc f is loosely mounted on the exterior of theboss or jour'nal'cl concentrically with the shaft Y and is attached bymeans of a suitable pin 9 remote from the center of rotation of the disc1 to a system of links and levers comprising a link k, a lever 7'connected to a lay shaft in having arms 0 adapted to pressvagainst pinsV for opening the compressor valves K. Upon rotation of the disc f in acounterclockwise direction, the link it is pulled downwardly, therebyopening the compres sor valves. Upon rotation of the disc 7 in aclockwise direction. thepin 9 assumes a position at the opposite side ofthe shaft Y whereupon the link his similarly held down.

It will be seen therefore that the compressor valves are opened uponrotation of the disc f in either direction.

The disc f is adapted to be actuated or rotated by one or more weights;0 which are spring pressed, as for instance by means of a coil spring9, to able slot '1' may be ormed in the periphery of the weights p toadmit the coil sprlng 9 so that the spring lies embedded in the weightsp. In order to rotate the weights p, a cover 8 keyed to the end of theshaft Y is provided with inwardly projecting pi'ns t engagin slots u inthe faces of the links p. The slots 11 extend radially and permit theweights p to. move radially outward and away from the disc f.Longitudinal movement of the weights p is prevented in either directionby the cover 8 and by a flange 'v of the disc f. If desired, a layer ofsuitable friction material w may be attached to the periphery of thedisc f to form a good gripgrip the disc 1. A suitand therefore pullingon the link 72. to open the compressor valve. As the compressoroperating motor speeds up, the shaft Y rotates more rapidlyand bycentrifugal force theweights p overcome the tension in the spring g,causing the weights to fly out- .Wardly disengaging the disc f,whereupon the link h, being released. permits the spider R to disengagethevalve K permitting them to function normally. Whlle operating at highspeed the disc f is free and there are no engaging surfaces to wear out.The outward movement of the weights p is limited by the circular flangea; surrounding the weights and formed integrally with the cover 8. I

The compressor operating motor (not shown) may be connected to the crankshaft C 'at the fly wheel y located on the crank shaftic exterior to thecasing A.

When operating normally the spiders R,

are held out of contact with the valves J by coil springs 2 within thespiders R and ressing against the valve seats H. .The unoading mechanismabove describedoperates against the tension of these springs to hold thevalves J off their seats H.

I claim:

1. In combination with a compressor and by cenlevers associated withsaid disc for opening 1 said compressor valves. 2. In combination with acompressor and its valves, a shaft adapted to be rotated by thecompressor, a disc journaled concentrically with the shaft, a pluralityof weights rotated by said shaft surrounding said disc, said weightsbeing spring pressed to engage said disc frictionally at slow speeds ofthe shaft and disengaged by centrifugal' force from said disc at highspeeds of the shaft, and a system of links and levers associated withsaid disc for opening said compressor valves.

3. In combination with a compressor and its valves, a shaft adapted tobe rotated by a compressor, a disc journaled concentrical- 1y with theshaft, a cover rigidly attached to the shaft, weights within said coverat- I tached thereto and spring pressed to engage said disc at slowspeeds of the shaft and adapted to be disengaged by centrifugal forcefrom said disc at high speeds, a link attached to said disc, a lay shaftadjacent the valves to be operated by said link, and

means associated with said lay shaft to open said compressor valves.

In testimony whereof I have signed this specification.

RAYMOND C. MOALLISTER.

